If you looking for low HOA, I recall the single family homes in West Irvine tract (off Jamboree) had monthly HOA of $45 few years back. But they don't have a swimming pool (if you care). In Irvine most detached homes only have 1 HOA (master), while attached condos/townhomes have 2 HOA's. Thee are exceptions, of course.
In California, we have prop 13, so your basic property tax rate is 1% of purchase price + limited annual adjustments. Most newish properties in Irvine have various assessments, bonds, and mello-roos. Most of the assessments are small-ish, the 2 biggest ones are "1915 AD BOND MB" and Mello-Roose. Mello-Roos vary by district. At border area with Tustin (Sheridan complex) it's Mello-Roos R4, at Oak Creek near UCI it's Mello Roos R2.
On the property tax bill, they usually list a phone # next to these items, so you can call and ask for info. I called about "1915 AD BOND MD" which is on property tax bill at both Oak Creek and Sheridan (prolly includes most of Irvine?) and they told me this bond expires in 2022 AD. The condo in Sheridan was built in 1999 and the annual 1915 AD BOND MD assessment is ~$500/y. The condo at Oak Creek was built in 2001 and the 1915 AD BOND MD is ~$900/year. Weird thing is the Sheridan place unit cost more than the Oak Creek/Oak Park one.
I couldn't get a live person on the phone to answer questions about Mello Roos R2. The person who answered the phone for Mello Roos R4 said that one expires in 2058. I'm a little iffy on that number because I recall there's supposed to be a reduction in 2010 (?). The HOA for both Sheridan and Oak Park are about $180/mo, both have dual associations.
There's a lot of choices in Irvine, you don't HAVE to buy a home with >$300/month HOA. Unless if you absolutely love the house and it has some awesome feng shui that makes you feel good every morning, I'd say give it a pass and look for something cheaper.